Many modern computer systems try to opportunistically reduce power consumption during periods of reduced activity. Common techniques include reducing or shutting down voltage power supply levels to one or more system components, stopping clocks, and so forth.
Different power consumption modes for computer systems have been dubbed Cn (or alternately Sn or Pn) states which indicate progressively greater power savings modes. The different modes often feature different wake latencies—the amount of time needed to resume a higher power mode. Thus, the choice of entering a particular power saving mode often requires a balancing between the amount of power savings and the amount of time needed to wake.